Dose-response effects of wild blueberries on appetite and cardiovascular health
| ISRCTN | ISRCTN11726069 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN11726069 |
- Submission date
- 28/10/2024
- Registration date
- 15/11/2024
- Last edited
- 30/10/2024
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English summary of protocol
Background and study aims
The aim of this study is to establish the dose-dependent ability of anthocyanin-rich wild blueberries to inhibit the post-meal rise in blood glucose and thereby activate gut-brain signalling through delayed starch digestion. Anthocyanins are found abundantly in blueberries and have been shown to have many beneficial activities. The study builds on the hypothesis that the presence of undigested starch along the gut can stimulate gut hormone secretion and thereby control appetite through gut-brain communication.
Who can participate?
Healthy male and female volunteers aged 18-56 years with no medical conditions and not taking medication
What does the study involve
Participants will be asked to come to the study facilities on four occasions to receive a placebo or blueberry product in three different dosages in a random order, with at least 5 days break between study visits. Participants will have measurements taken before consumption of a high-carbohydrate meal and the test drink.
Continuous glucose monitoring will be used to determine glucose response, and venous blood samples will be taken at each visit in regular 30-minute intervals up to 180 minutes to measure insulin and satiety hormone levels. Satiety will also be determined through hunger/satiety ratings taken periodically across the study day.
The researchers will also measure acute blood pressure changes following the intervention and perform cognitive tests at baseline and after 1.5 hours, timed to coincide with the expected maximum presence of anthocyanins in the circulation.
What are the possible benefits and risks of participating?
There are no direct benefits from participation in the study other than the participants being compensated for their time. There are a few risks to participation, mainly pertaining to drawing blood samples through cannulation which can leave bruises and is also associated with a risk of feeling dizzy or fainting.
Where is the study run from?
University of Leeds (UK)
When is the study starting and how long is it expected to run for?
June 2022 to October 2023
Who is funding the study?
Wild Blueberry Association of North America (USA)
Who is the main contact?
Dr Christine Bosch, c.bosch@leeds.ac.uk
Contact information
Principal Investigator
School of Food Science and Nutrition
University of Leeds
Leeds
LS2 9JT
United Kingdom
 ORCID ID |
0000-0001-6705-5709 |
|---|---|
| Phone | +44 (0)800 915 0402 |
| c.bosch@leeds.ac.uk |
Public, Scientific, Principal Investigator
School of Psychology
Leeds
LS2 9JT
United Kingdom
| ORCID ID |
0000-0002-0750-7248 |
|---|---|
| Phone | +44 (0)1133437000 |
| fs15lre@leeds.ac.uk |
Scientific
School of Food Science and Nutrition
Leeds
LS29JT
United Kingdom
| ORCID ID |
0000-0002-2331-4227 |
|---|---|
| Phone | +44 (0)800 915 0402 |
| l.dye@leeds.ac.uk |
Study information
| Study design | Single-centre randomized double-blind placebo-controlled crossover study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised cross over trial |
| Study setting(s) | University/medical school/dental school |
| Study type | Efficacy |
| Participant information sheet | 46302_PIS.pdf |
| Scientific title | Effects of wild blueberry on obesity – a pilot dose-response study targeting starch digestion and satiety through activation of gut-brain axis |
| Study objectives | The principal hypothesis of this study is that consumption of increasing concentrations of an anthocyanin-containing blueberry drink would decrease postprandial glucose concentration and increase satiety hormones in a dose-dependent manner. It was further hypothesized that a blueberry intervention would beneficially impact cognitive function under the postprandial high carbohydrate load, compared to placebo. |
| Ethics approval(s) |
Approved 24/03/2023, University of Leeds Psychology Ethics Committee (University of Leeds, Leeds, LS2 9JT, United Kingdom; +44 (0)113 343 7601 ; psyc-ethicssubmissions@leeds.ac.uk), ref: PSYC-855 |
| Health condition(s) or problem(s) studied | Reduction of postprandial glycaemia |
| Intervention | The study is conducted using a counterbalanced crossover trial design, with each participant acting as their own control. Participants will attend the lab on four separate occasions, separated by at least 5 days. After completing baseline measurements, participants will be asked to consume a high-carbohydrate breakfast (70 g carbohydrates) with a different study drink at each visit. Drinks include a placebo (0 mg anthocyanins) or three freeze-dried blueberry beverages containing 150, 300 or 450 mg anthocyanins. Interstitial glucose, blood pressure, Visual Analogue Scales and cognitive function are measured across a 3-hour study period as well as venous blood samples to analyse postprandial satiety hormone concentrations (insulin, GLP-1, PYY and GIP). Participants will be randomised to intervention order in a counterbalanced method using “visual basic for applications” coding in Excel. The same coding applies to counterbalancing each form of the cognitive tests. |
| Intervention type | Supplement |
| Primary outcome measure | Interstitial glucose measured by continuous glucose monitoring at baseline and every 15 minutes across a 3-hour postprandial period |
| Secondary outcome measures | 1. Blood pressure measured using an automatic blood pressure monitor at baseline and every 30 minutes 2. Appetite measured using visual analogue scales at baseline and every 30 minutes 3. Incretin hormones measured using venous blood samples from cannulation at baseline and every 30 minutes 4. Cognitive function measured using the Visual Verbal Learning test (VVLT), Corsi Block tapping test (Corsi) and the Rapid Visual Information Processing task (RVIP) at baseline and at 90 minutes after consumption of the drink |
| Overall study start date | 01/06/2022 |
| Completion date | 28/10/2023 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 56 Years |
| Sex | Both |
| Target number of participants | 24 |
| Total final enrolment | 24 |
| Key inclusion criteria | 1. Between 18 – 56 years of age 2. Body mass index (BMI) <27.0 kg/m2 3. Be in general good health (with no known food allergies/intolerances) 4. Not taking any medication/s known to affect blood pressure, blood glucose (like diabetic medication) or cholesterol 5. Not be pregnant or planning a pregnancy within the next 3 months. Not have been pregnant or lactating within the previous 6 months 6. Not menopausal 7. Like all the study foods and test products (checked at screening) 8. Be a non-smoker (for at least the last 6 months) 9. Sufficient fluency in the English language to be able to understand the study instructions and questionnaires 10. Willing to visit the laboratory for a screening session (1 hour) and 4 test mornings (8.00 am – 12.00 pm) |
| Key exclusion criteria | 1. Age <18 or >=56 years 2. BMI >27 kg/m2 3. Blood donation <3 months prior to the study or for the full duration of the study 4. Food allergy, intolerance, restriction or avoidance of the study beverage or control beverage or history of anaphylactic reaction to any food 5. Habitually consuming >14 units/week of alcohol in women or >21 units/week in men in the last 3 months 6. For women: pregnancy, lactation, perimenopause 7. No access to mobile phone and internet 8. Simultaneous participation in other relevant studies |
| Date of first enrolment | 01/04/2023 |
| Date of final enrolment | 28/10/2023 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
Leeds
LS29JT
United Kingdom
Sponsor information
Research organisation
Wild Blueberries
PO Box 100
Old Town
Maine
04468
United States of America
| Phone | +1 (0)207 581 1862 |
|---|---|
| administrator@WBANA-US.com | |
| Website | https://www.wildblueberries.com/health-benefits/research/ |
Funders
Funder type
Research organisation
No information available
Results and Publications
| Intention to publish date | 01/01/2025 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | Planned publication in a peer-reviewed journal |
| IPD sharing plan | The data sharing plans for the current study are unknown and will be made available at a later date |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | 30/10/2024 | No | Yes |
Additional files
Editorial Notes
28/10/2024: Study's existence confirmed by University of Leeds Psychology Ethics Committee.
